微米级液滴喷雾粒径谱的测量参数标定及其敏感性研究

Calibration and Sensitivity Study of Particle Size Spectrum of Micron Droplets Spray

液滴喷雾粒径谱可用于衡量喷雾雾化质量和雾化特性.测量喷雾液滴粒径分布的方法主要分为机械、电子和光学三类,其中以激光粒度仪为代表的光学方法的测量精度相对较高,被广泛用于液滴喷雾、固态粉尘等微粒的粒度分布测量.激光粒度仪测量结果受到测量参数的影响较大,值得深入研究.本文采用分体式激光粒度仪测量雾化液滴的粒径分布,主要研究了激光粒度仪在测量喷雾液滴粒度中的参数标定及敏感性问题.通过比较分析喷雾方向与粒度仪激光束不同夹角、喷口位置与激光束的不同垂直距离、喷口位置与粒度仪接收端的不同距离粒度测量结果,量化了上述三种不同测量参数对喷雾液滴的粒度分布测量结果的影响.研究认为,对微米级液滴喷雾粒径测量,建议选择自由分布模型对喷雾粒径进行拟合;喷雾方向应该垂直于激光束或略有偏转,偏转角度小于30°;建议喷口放置在激光束周围10cm范围内;粒度仪的接收端不宜距离样品太远,控制在20cm以内;V90的稳定性较差,不建议作为喷雾粒度的衡量特征,而建议采用稳定性较高的V10或V50.本研究有利于提高分体式激光粒度仪测量数据的质量.

Theatomized droplet size spectrum can be used to measure spray atomization quality and atomization characteristics.The methods for measuring the size distribution of particles can be mainly divided into three types:mechanical,electronic and optical.Among them,the optical method represented by laser particle analyzer has relatively high accuracy and is widely used for droplets,solid dust,etc.The measurement results of the laser particle analyzer are greatly affected by the measurement parameters with the need of further study.In this paper,the size distribution of atomized droplets is measured by a split laser particle size analyzer,and the parameter calibration and sensitivity analysis are presented.Comparing and analyzing different angles of the spray direction with the laser beam,different vertical distances between the nozzle position and beam,as well as different distances between the nozzle and the receiver,the three measurement parameters above are calibrated.The following conclusions are derived for micron-sized atomization droplets measurement from this study:(1)the free-distribution model is recommended to fit the particle size;(2)the spray direction should be perpendicular to the laser or slightly deflected with an angle less than 30°;(3)the nozzle should be placed within 10 cm around the laser beam;(4)the receiving end of the particle size analyzer should be within 20 cm;and(5)the stability of V90 is poor,and V10 or V 50 are recommended to be taken as the characteristic indicator with better stability.This study has important guiding significance for improving the measurement quality of the laser particle analyzer.